| Gerald William Reynolds | 1964 | 1965 |
| Peter Michael Kirk | April 1964 | October 1964 |
| John Albert Hay | 1 April 1964 | October 1964 |
| Harold James Boyden | January 1967 | October 1969 |
| Robert Crofton Brown | October 1974 | May 1979 |
| Philip Carter Goodhart | 5 January 1981 | 29 May 1981 |